This invention relates generally to means and methods for cleaning out sewer lines and relates, more particularly, to a rotatable saw blade used for cleaning a sewer line by rotating the blade and routing it through the sewer line.
A saw blade with which this invention is to be compared is commonly referred to as a root saw blade and includes an arcuate-shaped portion having a forward cutting edge which rotates along a circular path when the blade is rotated about an axis of rotation. During use, the saw blade is rotated about its rotation axis and directed cutting edge-first axially through the sewer line along a path which is substantially parallel to the rotation axis of the blade. As the saw blade is rotated and directed through the sewer line in this manner, debris and roots which might be clinging to the interior wall of the sewer line are severed from the interior wall by the rotating cutting edge.
Heretofore, the cutting edges of root saw blades of the prior art wear relatively rapidly during use which, in turn, reduces the useful working life of the prior art saw blades. Such rapid wear is believed to be due, at least in part, to the relatively large amount of heat which is generated as the root saw blade is rotated and directed through a sewer line. Such heat may be generated, for example, from the friction resulting from the contact between the outer surface of the rotating saw blade and the interior wall of the sewer line as the saw blade is directed therethrough. Furthermore, such heat is likely to accumulate in the blade when the blade continuously contacts, and thus rubs against, the interior wall of the sewer line as the saw blade is routed therethrough. In other words, as long as the blade continuously contacts the interior wall of the sewer line during use, there is little, if any, opportunity for the accumulated heat to dissipate from the saw blade.
It would therefore be desirable to provide a rotatable saw blade for cleaning a sewer line which has a longer working life than do root saw blades of the prior art.
Accordingly, it is an object of the present invention to provide a new and improved rotatable saw blade of the aforedescribed class.
Another object of the present invention is to provide such a saw blade which has a longer working life than do root saw blades of the prior art.
Still another object of the present invention is to provide such a saw blade which is less likely to experience an accumulation of heat during operation than do root saw blades of the prior art.
Yet another object of the present invention is to provide such a saw blade which has an increased capacity to sever debris or roots from the interior wall of a sewer line.
A further object of the present invention is to provide such a saw blade which is capable of being operated at relatively high rotational speeds and relatively high linear speeds yet effectively cut through debris and roots and relatively stiff items, such as polyvinylchloride (PVC) pipe, which might protrude into the interior of the sewer line being cleaned with the saw blade.
A still further object of the present invention is to provide such a saw blade which is uncomplicated in structure, yet effective in operation.